Hammer mill



May 22, 1945. H. M. JOHNSTON HAMMER MILL Filed April 24, 1943 4Sheets-Sheet l IN VEN TOR. Hom/DMJoH/YsTo/v INVENTOR.

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HAMMER MILL Filed April 24, 1945 4'Sheets-Sheet 5 INVENTOR. HOWARD M,JOHNSTON Arron/ver May 22, 1945. H. M. JoHNsToN v2,376,361

HAMMER MILL Filed April 24, 1945 4 sheets-sheet 4 INVENTOR. How/:R0/YJOH/ysron ATTORNEY Patented May 22, 1945 UNITED STATES PATENT ori-ICEHAMMER MILL Howard M. Johnston, Toronto, Ontario, Canada, assignor toMassey-Harris Co. Ltd., Toronto, I Ontario, Canada, a corporation ofCanada Appucsnnn April 24, 194s, serial No. 484,353

2 claims., ((1241-51) The present invention relates to a grinding millof the hammer type and an object of the invention is to provide a millthat will deliver a more uniformly ground product `than other mills ofthe class.

Another object of the present invention is to provide a mill that willoperate on less power per 100 pounds of feed ground than other mills.

Still another objec of my invention is to provide a mill which can bemade largely of sheet or bar stock and having a larger capacity thanother mills of the same size, weight or cost.

A further object of my invention is to provide a. mill through which thematerial iiows continuously and on a direct path; thus to avoid aslowing down of the material because of pockets or unnecessary turns.

An important object of the present invention is to provide a millwherein it is not necessary to operate under a vacuum high enough topick the ground material from the bottom of the housing for deliveringit to a bagging attachment.

An important object of my invention is to provide a mill in which theground particles may pass through the screen any place within the 360diameter of thescreen.

A further object of my invention is to give the material maximumopportunity to pass through the screen when it has been ground to thesize of the openings in the screen so that it will not be furtherreduced in size.

A still further object is to provide an auxiliary air inlet in order togive the operator better control over the grinding and discharging ofthe material.

The above objects are accomplished by means of a screen which entirelysurrounds the rotor and by providing an annular chamber around thescreen through which booster blades revolve fan like so the ground feedis immediately swept from the screen after it has pa/ssed therethroughand then moved rapidly in direct lines from the annular chamber to theoutlet.

An important object of the present invention is to provide a mill whichcan be made in very small or very large sizes without departing fromitsutility which is commensurate with its capacity.

To these and other useful ends, my invention consists'of parts,combinations of parts, or their equivalents, and mode ofI operation, ashereinafter described and claimed and shown in the accompanying drawingsin which:

Fig. 1 is a side elevational view of my improved mm with the access udlifted. y

Fig. 2 is a sectional view taken on line 2-2 of Figure 1.

Fig. 3 is a sectional view taken on line 3-3 of Figure 2.

t the rotor is,` in its entirety, designated by reference character B.Member A comprises side panels Ill and II and an outer wall I2 whichterminates as at I3 and I4. Side panels I0 and f II are cut-away onlines I5 and I6.

A lid which in its entirety is designated by reference character C isformed by means of side plates I'I and I8 and a cover I9 which is hingedto member I2 as at 20. When lid C is closed, as illustrated in Figure 3,means (not shown) is provided for locking the lid in its closed positionas at I3 Members I8, II, I2, I1, I8 and I9 complete the housing member.

Members I0, II, I1 and I8 are cut-away so as Vto form concentricallypositioned openings 25 and 26. Bearings 21 and V28 are rigidly securedto members Ill and II concentrically with openings 25 and 26. A shaft 3|is rotatably mounted in bearings 21 and 28 as illustrated, the shaft atone end protruding through bearing 28 and havingl means secured to thisend preferably a suitableV pulley for driving the shaft.

Member B comprises a hub positioned on shaft 3| in a. manner clearlyillustrated in Figure 2. I provide a supplemental partition 36 which iscircular land terminates at its periphery asat 3B.

I provide a removable screen preferably formed in three parts 39, 4U and4I and being secured to members I0 and 36 in a manner whereby eachscreen member may ,be removed when lid C is lifted. These three screensare carried on guide bars 42-42 which are secured to members I0 and 36providing a rotor chamber 43 and an annular chamber 44. Annular chamber44 is interconnected with the space formed by members I I, I8 and 36. Imount a fan blade carrying member 45 on hub 35, this E" member havingpreferably three arms 46 secured thereto which extend to within a shortdistance of members I 2 and I9 (see Figure 2).' On each arm I mount abooster or fan blade 4'I, the blade extending into chamber 44 about asshown in Figure 2. ,Member 35 comprises a number Iof sections betweenwhich arms 48 extend, the' hub thus formed being preferably keyed to theshaft and made taut against members 48 by means of end nuts 49-49.

I have shown two members 48 positioned as illustrated in Figure 3through which the shaft extends. In, order to lock members 48 to the hubmember, I provide a number of locking pins 50 so the arms and ,hub willbe rmly locked by trictional contact between nuts 49 or a suit able keymay be provided for locking the members rigidly together and to theshaft.

I provide preferably two wearing plates 55 on each end of members 4l.These plates in the larger machines are made removable and reversible sowhen the corners become badly worn, they may be turned for wear on theother corner and when both corners at one end are badly worn, then theymay be reversed so the other ends of these plates will be serviceable.

I provide an inlet opening 56 in member I0 anda feed-in trough which inits entirety is designated by reference character D. This trough isprovided 'with a bottom 51 and side plates 58 and 59, the side plateshaving the shape shown in Figure 2. A gate valve 80 is provided forregulating the volume of material fed into the machine.

Between members Ill and 80 I mount a screen 6I. Clearly if ilne grain isbeing lfed into the machine for grinding and member 60 is left open onlyfar enough to permit the right volume to v enter the grinder, there willbe no air permitted to enter the grinder. Mills of the class require acertain volume of air which is drawn through the grinding chamber andscreen.

In the presenty design, a vacuum is set up by the action of blades 41and this vacuum will cause air to be drawn through screen 6I and intothe rotor chamber through inlet 56. Blades 41 will act to draw the feedparticles through the screen as soon as they are small enough to passthrough openings S3 in the screen and discharge the ground feed throughan opening 54 in housing member I2. Clearly the fan will actcentrifugal- 1y to move the material as it leaves the screen directlyinto outlet 84.

It will be seen that the path from inlet 56 to outlet 64 is short anddirect and that there is no place within the rotor chamber or within theannular chamber where the material will be retarded in its directmovement through the machine and that there is no place for the groundmaterial to lodge so that immediately after it passes through thescreen, it will be swept into the outlet.

In Figures 1, 2 and 3 or for the smaller sized machines, four suitablyshaped legs 10 may be used as a mounting for the device. In Figures 4and 5 the mounting is somewhat heavier and may be formed as illustratedin these gures having preferably transverse supporting blocks 1I-1 I. Inthis design, I provide a feed-in trough which in its entirety isdesignated by reference character E. The trough proper terminates as at12 and having gate valves 13-13 for regulating the iiow of grain intothe machine, the trough having an extension 14 which surrounds an open'-ing in the side wall similar to opening 56 in the other figures.Extension 14 is provided with'a covering 15 and a screened opening 16which acts similar to screen 8| in the other figures.

In the larger mills, it has been found that it is necessary to controlthe volume of air entering the mill through screen 15. For this purpose,I provide a gate valve 11 hingedly mounted on member 15 as at 18 andhaving means 19 whereby the valve may be locked in any desired positionfor the purpose of regulating the volume of air entering the machine.

In Figure 2 I illustrate a V-belt drive pulley on asvasci It will beseen that 'the material will all beY held in suspension from the time itleaves the screen until it enters the outlet and that the fan blades,sweeping close to and along the outside surface of the screen, will actto urge the material through and away from the screen immediately afterit is small enough to pass through the screen to prevent the particlesfrom rebreaking and forming fine dust particlesT Since the screensurrounds theV rotor for 360, the rotorwill operate with minimum powerand maximum eiliciency and have very large output capacity.

Obviously a minimum vacuum will be required since the path from thescreen to the outlet is direct and the ground material is not permittedto slow down or come to rest on guideways or on the bottom of thehousing as in other mills; thus in addition to the power saved in thegrinding process, there will also be a great saving of power required tomove the material from the screen to the outlet.

By scrutinizing the drawings it will be seen that when the housing lidis lifted, all of the 'operating parts of the mill may be moved in fullview of the operator.

Clearly my device will occupy minimum space relative to capacity and canbe easily manufactured at low cost.

Having thus shown and described my invention,

I of the housing and being somewhat smaller in diameter than thehousing, a screen secured to the periphery of said supplementalpartition and to the other wall of the housing forming a rotor rchamberand an annular chamber on the outside of the screen, said annularchamber being interconnected with the narrow space between the firstwall and supplemental partition, a shaft concentrically rotatablymounted in the walls of said housing and means for turning the shaft, arotor mounted on said shaft within said chamber, a fan member secured tosaid shaft and extending outwardly between said partition and rsthousing l wall and a distan-ce past the transverse plane of said screenand having mounted thereon spaced fan blades positioned in said annularchamber and intermediate the screen and the outer wall of the housing,an inlet in said rotor chamber and an outlet in the wall oi the housing,said outlet being positioned and shaped to thereby act as a fan andground feed outlet.

2. A device as recited in claim 1 including; said inlet having a feed-intrough and a gate valve spaced a distance from'the inlet for regulatingthe volume of feed entering the device, means forming a closure for theytrough between said gate valve and inlet, having an air inlet and a gatevalve therefor whereby the air entering the air inlet may be manuallycontrolled.

HOWARD M. JOHNSTON.

